REPURPOSING OR SECONDARY USE OF KNOWN DRUGS

Repurposing of drugs was most often a strategic approach, though by “serendipity” in few instances. Early practice of pharmacovigilance in USA, led to near ‘serendipitous’ addition to market value for many “first use” drugs. Glaxo-Welcome’s Bupropion brand “Wellbutrin” was first approved for treatment of depression. While “Wellbutrin” received an average response in the anti-depression segment, pharmacovigilance reports to FDA was perplexing. Patients gave conflicting response. While a few wanted to change to another drug, many others wanted to continue the use of the prescribed drug even after being advised to stop. The reason when investigated, was that the patients felt the urge to discontinue smoking, which was acceptable to some, while not to others. When this finding was received by the FDA from multiple specialists, Glaxo-Welcome was asked to conduct a full study on a priority basis. Consequently, FDA granted a fast track approval for use of Bupropion for smoking cessation. Antidepressant “Wellbutrin” opened up new pathway for smokers to “kick the Butts” through its second use “Avatar”, in form of “Zyban” for smoking cessation and become the first global breakthrough drug of choice for this second use. Pharmacovigilance helps in developing a road map for secondary use.